Children with diffuse pontine gliomas have a dismal prognosis. Because surgery in this area is difficult, radiation therapy has been the mainstay of treatment. Although some children may improve clinically after radiation therapy, the effect is short-lived and almost all progress within several months. Chemotherapy has not had a significant impact on survival. Interferon-alpha is a cytokine that has been studied in patients with gliomas and has demonstrated some activity in prior clinical trials. Recent in vitro data suggest that higher antitumor activity may be demonstrated when there is continuous low-dose exposure to interferon-alpha. In this study, we plan to administer pegylated interferon alfa-2b (PEG-Intron') subcutaneously once a week to pediatric patients with diffuse pontine gliomas who have completed radiation therapy.